Modified hydrocarbylphenol-aldehyde resins for use as tackifiers and rubber compositions containing them

ABSTRACT

The invention relates to a modified hydrocarbylphenol-aldehyde resin prepared by reacting a hydrocarbylphenol-aldehyde resin with a primary or secondary amine and further with an epoxide. The invention also provides a process for preparing a modified, hydrocarbylphenol-aldehyde resin and a rubber composition containing such resin.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent Application No. 60/842,160, filed Sep. 5, 2006,hereby incorporated by reference in its entirety.

FIELD OF INVENTION

This invention relates to modified hydrocarbylphenol-aldehyde resinsuseful as tackifiers in rubber and a process for preparing such resins.In particular, the invention relates to hydrocarbylphenol-aldehyderesins modified with primary or secondary amines and then furthermodified with an expoxide.

BACKGROUND OF THE INVENTION

Rubber products today are made from natural rubber and synthetic rubberor blends thereof. Natural rubber (NR) differs from synthetic rubber.Natural rubber is made from the milk of the rubber tree. This rubbermilk, called latex, is a colloidal dispersion in an aqueous medium. Onlysmall percentage of the latex is used directly and the greatest part isprocessed into hard rubber. Among many different types of syntheticrubbers, the most common synthetic rubbers are SBR (styrene butadienerubber), BR (butadiene rubber), EPDM (ethylene propylene diene rubber),IR (isoprene rubber), IIR (isoprene isobutylene rubber), NBR(acrylonitrile butadiene rubber), SIS (styrene isoprene styrene), SBS(styrene butadiene styrene) and CR (poly-2-chlorobutadiene). Examples ofrubber products include, but are not limited to, conveyor belts, flatand vee-belts, tires, sole material, sheet material, and punchingproducts.

Rubber products are frequently made up of several rubber layers eachwith the same or a different chemical composition. During this “buildup”, the rubber layers must adhere to one another adequately in theirpre-vulcanized state. For example, an assembled tire blank is requiredto hold together for a fairly long period prior to vulcanization. It istherefore important that the rubber mixtures used have an adequate“tack.” The property termed “tack” is defined as the force required topull apart two pre-vulcanized rubber mixtures which have been pressedtogether under certain defined conditions. While natural rubber mixturesgenerally have good tackiness, mixtures of synthetic rubbers are muchless tacky and, in extreme cases, possess no tackiness at all.Therefore, it has been common practice to add a tackifier to less tackyrubbers or rubber mixtures to increase their tack. In synthetic rubberproducts, synthetic rubber adhesive compositions are employed to improvetack and provide good cured adhesion.

Rubber compositions containing a tackifier are generally formulated ininternal mixers or on sets of rollers from a natural or synthetic rubber(e.g. styrene-butadiene copolymers, polybutadiene) or mixtures thereof.Rubber compositions also typically contain additives known in the artsuch as fillers, processing agents and vulcanizing agents. Afterformulation, the rubber composition is then used to manufacture adesired rubber product. As mentioned above, the rubber composition mustremain sufficiently tacky during the manufacturing process, even whenthe process is interrupted for fairly long periods, which is not unusualparticularly when manufacturing involves processes at differentlocations or requires storage and/or transport of pre-finished goods.

Even though a number of different materials are currently used astackifiers, there remains a need to develop tackifiers which providesrubber compositions with increased tack. A particular need exists in thetire industry because of the poor tack of synthetic rubber compositions,such as commercial SBR-based tire compositions.

This invention answers that need. Tackifying resins of the invention,modified hydrocarbylphenol-aldehyde resins, have improved tackperforming as good as or better than current tackifiers. The inventionalso provides a process for preparing modifiedhydrocarbylphenol-aldehyde resins and an improved rubber compositioncontaining such resin.

SUMMARY OF THE INVENTION

The invention relates to a modified hydrocarbylphenol-aldehyde resinprepared by reacting a hydrocarbylphenol-aldehyde resin with a primaryor secondary amine and further with an epoxide. More particularly, theprimary or secondary amine is one suitable for use in a Mannichcondensation reaction with a hydrocarbylphenol-aldehyde resin. A processfor preparing a modified, hydrocarbylphenol-aldehyde resin is anotherembodiment of the invention. In another aspect, the invention relates toa rubber composition having improved tack comprising a rubber ormixtures of rubbers with a modified hydrocarbylphenol-aldehyde resin ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention is directed to a modified hydrocarbylphenol-aldehyde resinprepared by reacting a hydrocarbylphenol-aldehyde resin with a primaryor secondary amine and further with an epoxide, preferably, an epoxideof C₄-C₆₀-olefin. A hydrocarbylphenol-aldehyde resin modified with aprimary or secondary amine, Formula (I) below, is reacted with of anepoxide, preferably about 1 to about 25 weight percent, in the presenceof a basic catalyst and at a basic pH.

wherein

R₁ is a straight or branched C₁-C₃₀ alkyl;

R₂ is —CHR₅,

-   -   wherein R₅ is an amine containing an amino group having at least        one active hydrogen atom of the formula (i)

-   -   wherein R′ and R″ are independently H, C₁-C₆ alkyl, C₂-C₆        alkenyl, C₂-C₆ alkynyl, or wherein R′ and R″, together with the        N carrying them, form a 5-7 membered heterocyclic ring; or    -   an alkylene polyamine of the formula (ii)

-   -   wherein A is a divalent alkylene radical having 2 to 6 carbon        atoms and x is an integer from 1 to 10;

R₃ is R₂ or a mixture of R₂ and H and/or —CHR₅OH;

R₄ is H or C₁-C₄ alkyl; and

m plus n is at least 1.

The term “hydrocarbyl phenol-aldehyde resin” generally refers to a resinprepared reaction product of a hydrocarbylphenol with an aldehyde.

The term “hydrocarbylphenol” refers to a compound that includes at leastone hydroxy functional group attached to a carbon atom of an aromaticring and having at least one hydrocarbyl substituent. Illustrativehydrocarbyl phenols include, but are not limited to alkylated phenolsand multi-hydroxy phenols, and hydroxy-substituted multi-ring aromatics.Illustrative alkylated phenols include methylphenol (also known ascresol), dimethylphenol (also known as xylenol), 2-ethylphenol,pentylphenol and tert-butyl phenol. “Multi-hydroxy phenolic compound”means a compound that includes more than one hydroxy group on eacharomatic ring. Illustrative multi-hydroxy phenols include1,3-benzenediol (also known as resorcinol), 1,2-benzenediol (also knownas pyrocatechol), 1,4-benzenediol (also known as hydroquinone),1,2,3-benzenetriol (also known as pyrogallol), 1,3,5-benzenetriol and4-tert-butyl-1,2-benzenediol (also known as tert-butyl catechol).Illustrative hydroxy-substituted multi-ring aromatics include4,4′-isopropylidenebisphenol (also known as bisphenol A),4,4′methylidenebisphenol (also known as bisphenol F) and naphthol.

The term “hydrocarbyl” means a hydrocarbon substituent includingaliphatic (straight-chain and branched-chain), and a cyclic substituentsuch as alicyclic, aromatic, and cyclic terpenes. Preferably, thehydrocarbyl group of the hydrocarbylphenol-aldehyde resin is a straightor branched C₁-C₃₀ alkyl group. More preferably, the hydrocarbyl groupis a straight or branched C₁-C₁₅ alkyl group. Most preferably, thehydrocarbyl group is butyl or octyl. The hydrocarbyl group may besubstituted with common functional groups such as hydroxyl groups, aminogroups, carboxylic groups, halogens, thiol groups, disulfide groups,etc. The functional groups should not impair the tackifying propertiesof the modified, hydrocarbylphenol-aldehyde resin of the invention or ofa rubber composition to which the resin is added. Preferably, anyfunctional group is chosen to add beneficial properties to the resin formanufacturing purposes, for increased tack, or for improving theproperties of the rubber composition to which it is added.

An “aldehyde” is a compound having the generic formula RCHO.Illustrative aldehyde compounds include formaldehyde, acetaldehyde,propionaldehyde, n-butylaldehyde, n-valeraldehyde, caproaldehyde,heptaldehyde and other straight-chain aldehydes having up to 8 carbonatoms, as well as compounds that decompose to formaldehyde such asparaformaldehyde, trioxane, furfural, hexamethylenetriamine,benzaldehyde, aldol (β-hydroxybutraldelhyde), acetals that liberateformaldehyde on heating.

Hydrocarbylphenol-aldehyde resins are known in the art. Anyhydrocarbylphenol-aldehyde resin may be used to form the modified resinsof the invention. Preferred hydrocarbylphenol-aldehyde resins useful inthis invention are the condensation products from the interactionbetween phenol, C-alkyl substituted phenols (including cresols,xylenols, p-tert-butyl-phenol, p-phenylphenol and nonyl phenols),diphenols, e.g. bisphenol-A (2,2-bis(4-hydroxyphenyl)propane), andaldehydes such as formaldehyde, acetaldehyde, chloral andfurfuraldehyde.

The polymerization of phenols with formaldehyde to preparehydrocarbylphenol-aldehyde resins is well known in the art. The type ofcatalyst and the molar ratio of the reactants used in the preparation ofphenolic resins determines their molecular structure and therefore thephysical properties of the resin. An aldehyde:phenol ratio between 0.5:1and 1:0.1 usually 0.5:1 to 0.8:1, and an acid catalyst is used toprepare those phenolic resins generally known as novolak resins whichare thermoplastic in character. Higher aldehyde:phenol ratios of morethan 1:1 to 3:1, and a basic catalyst give rise to a class of phenolicresins known as resoles, and these are characterized by their ability tobe thermally hardened at elevated temperatures. Both these classes ofhydrocarbylphenol-aldehyde resins, novolak and resoles, are useful inthis invention.

The highly exothermic condensation reaction, the so called “novolakcondensation”, is carried out by a method that hydrocarbylphenols reactwith aldehydes or ketones, especially formaldehyde, in the presence ofcatalysts, as a rule in the presence of acids, to formhydrocarbylphenol-aldehyde novolak resins (U.S. Pat. No. 4,167,540; U.S.Pat. No. 6,642,345). Preferably, the hydrocarbylphenol-aldehyde novolakresins are a line of novolak resins manufactured by SI Group ofSchenectady, N.Y., such as the SP-1068, HRJ-2765, HRJ-4047, HRJ-10420,CRJ-418, HRJ-2355, SMD 31144, and HRJ-11937 resins.

Base-catalysed phenol formaldehyde resins, resole resins, are made withan aldehyde to phenol ratio of greater than one (usually around 1.5).For example, phenol, formaldehyde, water and catalyst are mixed in thedesired amount, depending on the resin to be formed, and are thenheated. Although any base can be used from caustic NaOH to amines,preferably the base is TEA (triethylamine) or TEAOH (triethanolamine).The first part of the reaction, at around 70° C., forms hydroxymethylphenols. Hydroxymethyl phenols will crosslink on heating to around 120°C. to form methylene and methyl ether bridges. It is this highlycrosslinked nature of phenolic resin which gives them their hardness andtheir excellent thermal stability, thermosets, and which makes themimpervious to most chemical attack and solvation. Preferably, thehydrocarbylphenol-aldehyde resole resins are a line of resole resinsmanufactured by Schenectady International Inc., such as SP-1045, SP-1055and SP-1056 resins.

Representative amine reactants used to prepare the modifiedhydrocarbylphenol-aldehyde resins of the invention are primary orsecondary amines, which are suitable for use in a Mannich condensationreaction. As mentioned above with regard to Formula (I), the aminemoiety may have alkyl, alkenyl, alkynyl, or aryl substituents. The aminemay also be a cycliclic amine which may be saturated or unsaturated,aromatic, or contain other heteroatoms in addition to the aminenitrogen. The amine may further be a polyamine. Examples of such aminesare, but are not limited to, mono and di-amino alkanes and theirsubstituted analogs, e.g., ethylamine, dimethylamine,dimethylaminopropyl amine and diethanol amine; aryl amines and diamines,e.g., aniline, naphthylamine, benzyl amine, phenylene diamine, diaminonaphthalenes; heterocyclic amines, e.g., morpholine, pyrrole,pyrrolidine, imidazole, imidazolidine, and piperidine; melamine andtheir substituted analogs. Other representative amines are alkylenepolyamines, principally polyethylene polyamines. Suitable alkylenepolyamine reactants include ethylenediamine, diethylene triamine,triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine,hexaethylene heptamine, heptaethylene octamine, octaethylene nonamine,nonaethylene decamine, decaethylene undecamine and mixtures of suchamines having nitrogen contents corresponding to the alkylenepolyamines. Corresponding propylene polyamines such as propylene diamineand di-, tri-, tetra-, penta-propylene tri-, tetra-, penta- andhexa-amines are also suitable reactants. Morpholine is a particularlypreferred amine for use in this invention.

The reaction of primary and secondary amines, in particular morpholine,with hydrocarbylphenol-aldehyde resins via a Mannich reaction is knownin the art. U.S. Pat. Nos. 2,040,039 and 2,040,040 disclose the ease ofthe condensation of alkylated phenol, formaldehyde and morpholine toform the corresponding morpholinomethylenephenols. U.S. Pat. No.3,001,999 discloses the reaction of p-alkylphenol with formaldehyde andamines, including morpholine. U.S. Pat. Nos. 3,173,952 and 2,997,445disclose the aminoalkylation of dialkylphenols; German Patent No.2,320,526 discloses aminoalkylation using diethanolamine. U.S. Pat. Nos.4,146,512 and 4,146,513 disclose that aminomethylene terminatedalkylphenols and polymers thereof, when the amine group is morpholine oramines which can be dehydrated to morpholine such as diethanolamine anddi-2-hydroxy propylamine, impart good tack properties to uncured rubberand provide good tack retention.

After modified with the primary or secondary amine, thehydrocarbylphenol-aldehyde resin is further modified with an epoxide,preferably an epoxide of C₄-C₆₀ α-olefin. The hydroxyl functionalityremaining on the hydrocarbylphenol-formaldehyde resin reacts with theepoxide. The resulting resins shows increased tack when used in a rubbercomposition. The epoxide used in the invention is preferably an expoxideof a C₄-C₆₀ α-olefin, more preferably a straight chain C₄-C₂₂ epoxide,and even more preferably, a straight chain C₆-C₁₆ epoxide.

The invention also provides a process for producing a modified,hydrocarbylphenol-aldehyde resin. The process for preparing a modified,hydrocarbylphenol-aldehyde resin having improved tack comprises the stepof:

-   -   (a) reacting an epoxide, preferably about 1 to about 25 weight        percent, in the presence of a basic catalyst and at a basic pH,        with an amine-modified hydrocarbylphenol-aldehyde resin of the        Formula (I)

-   -   -   wherein        -   R₁ is a straight or branched C₁-C₃₀ alkyl;        -   R₂ is —CHR₅,            -   wherein R₅ is an amine containing an amino group having                at least one active hydrogen atom of the formula (i)

-   -   -   -   wherein R′ and R″ are independently H, C₁-C₆ alkyl,                C₂-C₆ alkenyl, C₂-C₆ alkynyl, aryl, or wherein R′ and                R″, together with the N carrying them, form a 5-7                membered heterocyclic ring; or an alkylene polyamine of                the formula (ii)

-   -   -   -   wherein A is a divalent alkylene radical having 2 to 6                carbon atoms and x is an integer from 1 to 10;

        -   R₃ is R₂ or a mixture of R₂ and H and/or —CHR₅OH;

        -   R₄ is H or C₁-C₄ alkyl; and

        -   m plus n is at least 1.

As mentioned above, any hydrocarbylphenol-aldehyde novolak resin orresole resin may be used to form the modified resins of the invention.The resin is first modified with an amine to form resin such as inFormula (I) followed by epoxide modification. The reactions may becarried out sequentially in a single reaction vessel or as separatereactions isolating each or a desired intermediate product. Themodification process is carried out in a reactor, for example acustomary vessel or glass flask which is equipped with a stirrer,heater, thermostat, feeding device, reflux condenser and waterseparator. The hydrocarbylphenols may be initially introduced with thecatalyst and brought to the desired reaction temperature or distillationtemperature, and the aldehydes or ketones, preferably for exampleaqueous formaldehyde solution, is added over a period of a few hours. Itis also possible to initially introduce only a part of thehydrocarbylphenols and to add the rest along with the formaldehyde at90-150° C.

Modified, hydrocarbylphenol-aldehyde resins prepared according to theinvention are useful as tackifiers in rubber compositions. In thisembodiment of the invention a modified, hydrocarbylphenol-aldehyde resinis added to a rubber composition to improved the tack of the rubber. Therubber composition may be any natural rubber, synthetic rubber or amixture thereof, such as discussed above. A modified,hydrocarbylphenol-aldehyde resin according to the invention may be addedto a rubber composition in the same amount, in the same manner and forthe same uses as other known tackifiers. Preferably, the modified resinis used in amount ranging from 0.5 to 7 phr, and more preferably from 1to 4 phr. A single modified resin according to the invention or amixtures of the resins may be incorporated in the rubber composition.Accordingly, rubber compositions containing a modified,hydrocarbylphenol-aldehyde resin is another embodiment of the invention.Rubbers can be used in any desired supplied form, for example as balesor powders and also, for example, with carbon black. Other customaryadditives may also be used in a rubber composition of the invention.These additives include, but are not limited to, fillers, vulcanizingagents, accelerators, activators and processing auxiliaries. Thevulcanizates obtained containing a modified, hydrocarbylphenol-aldehyderesin according to the invention can, for example, be used as industrialrubber goods, such as damping elements, rubber sleeves, bellows,conveyor belts and also for vehicle tires.

The process of the invention is further illustrated with reference tothe following examples. The following tackifying resins were used forcomparison in the examples below. All are available from SI Group,Schenectady, N.Y.

-   -   T8000 tackifier, a t-Octylphenol formaldehyde tackifying resin    -   T2300 tackifier, a t-Butylphenol formaldehyde resin;    -   T6000 tackifier, a t-Octylphenol formaldehyde resin; and    -   T2000 tackifier, a t-Butylphenol formaldehyde resin.

EXAMPLE 1 Preparation of Modified Hydrocarbylphenol-Formaldehyde ResinsPreparation 1 of a Modified Octyl Phenol-Formaldehyde Novolak Resin,“Resin O”

A hydrocarbylphenol-formaldehyde novolak resin was prepared by reacting100 pounds p-tertiary octylphenol and 27 pounds of 50% aqueousformaldehyde in the presence of 69 grams of an acidic catalyst, (DDBSA(dodecyl benzene sulfonic acid)), heated to 90° to 110° C. withagitation. This reaction, a “novolak condensation,” was held for 1 to 3hours.

After the novolak condensation was complete, the pH of the reactionmixture was switched to a basic pH by addition of triethanolamine forsubsequent reaction of the hydrocarbylphenol-formaldehyde novolak resinwith morpholine. 9 pounds of morpholine was added to the reactionmixture and then 6.25 pounds of 50% formaldehyde was slowly added to thereaction mixture and reacted over 1 hour. Reaction times of about 0.5 toabout 5 hours, with typical reaction times of about 2 hours.

Epoxy modification: 25 pounds of 1,2 epoxyhexadecane was added to thereaction mixture. After the reaction was complete, the contents werevacuum distilled to a temperature of 180° C. at 25-29 mbar vacuum toremove any residual material.

Preparation 2 of a Modified Octylphenol-Formaldehyde Resole Resin,“Resin O”

The starting material, a p-tertiary octyl phenol-formaldehyde resoleresin, was the commercially available resole resin, SP 1045,manufactured by SI Group. The first step of the preparation was amodification of a hydrocarbylphenol-formaldehyde resole resin, SP 1045,with morpholine. 1000 g of SP 1045 was reacted with 100 grams morpholinein the presence of 50 grams of triethylamine as a catalyst. The reactionmixture was heated to 50 to 100° C. to ensure complete reaction, about 1hour. Reaction times of about 0.5 to about 5 hours, with typicalreaction times of about 2 hours. When the reaction was complete, thecatalyst was removed via vacuum distillation.

Epoxy modification: 100 grams of 1,2 epoxyhexadecane was added to thereaction mixture and after the reaction was complete, the contents werevacuum distilled.

Preparation 3 of a Modified Octyl Phenol-Formaldehyde Novolak Resin,“Resin O”, In Situ

To form an initial reaction mixture 1000 gram of p-tertiary octylphenol, 100 g of morpholine and 10 g NaOH were combined. The reactionmixture was heated to 90° C. 288 gram of 50% aqueous formaldehydesolution was then added to the reaction mixture and the reactionmixtures were held at 90° C. for 1 to 5 hours. 10 gram of 98% sulfuricacid was then added to the reaction mixture to convert the in situ resinto a novolak resin. The contents were vacuum distilled to 150° C.

Epoxy modification: 100 grams of 1,2 epoxyhexadecane was added to thereaction mixture and after the reaction was complete, the contents werevacuum distilled.

Preparation of a Modified Butyl Phenol-Formaldehyde Novolak Resin,“Resin B”

Modified butyl phenol-formaldehyde resins of the invention were preparedin the same manner as described above for Resin O, only substitutingp-tertiary butyl phenol for p-tertiary octyl phenol or an p-tertiarybutyl phenol-formaldehyde resole resin in the above methods. These aregeneral methods for the preparation of modified hydrocarbylphenol resinsof the invention.

EXAMPLE 2 Preparation and Evaluation of Rubber Compositions A. RubberCompositions

The following rubber compositions, Tables 1-4, were prepared by two-passBanbury mixing according to ASTM D3182-89.

TABLE 1 30/70 NR/BR rubber composition Composition Phr Natural rubber 30Butadiene rubber 70 Carbon Black 70 Zinc Oxide 3 Stearic Acid 1Antioxidant 0.25 Aromatic Oil 16.5 Ozone protective wax 0.56-p-Phenylenediamine 1 Sulfur 2 N-tert-2-benzothiazolesulfonamide 3N-cyclohexylthiophthalimide 0.2 Tackifying Resin 4

TABLE 2 70/30 SBR/BR rubber composition Composition phr Styrenebutadiene rubber 70 Butadiene rubber 30 Carbon Black 70 Zinc Oxide 6Stearic Acid 1.5 Aromatic Oil 33 6-p-Phenylenediamine 1 Sulfur 1.8N-tert-2-benzothiazolesulfonamide 1.8 Tackifying Resin 1

TABLE 3 100% Natural Rubber, NR Blank Composition Phr Natural rubber 100Carbon Black 55 Zinc Oxide 6 Stearic Acid 2 HMT 2.5Hexamethylenetetramine Aromatic Oil 4 Silica 15 6-p-Phenylenediamine 1Sulfur 2.5 N-tert-2-benzothiazolesulfonamide 0.9 Tackifying Resin 0

TABLE 4 100% Natural Rubber, NR Composition Phr Natural rubber 100Carbon Black 55 Zinc Oxide 6 Stearic Acid 2 HMT 2.5Hexamethylenetetramine Aromatic Oil 4 Silica 15 6-p-Phenylenediamine 1Sulfur 2.5 N-tert-2-benzothiazolesulfonamide 0.9 Tackifying Resin 4 phr= per hundred rubber

B. Evaluation of Rubber Compositions

Rubber compositions containing tackifying resins of the invention wereevaluated using the following tests:

Mooney Scorch, ASTM D1646-03: Standard Test Methods forRubber-Viscosity, Stress Relaxation, and Pre-VulcanizationCharacteristics (Mooney Viscometer). Mooney viscosity is defined as theshearing torque resisting rotation of a cylindrical metal disk (orrotor) embedded in rubber within a cylindrical cavity. When diskrotation is abruptly stopped, the torque or stress on the rotordecreases at some rate depending on the rubber being tested and thetemperature of the test. This test measures this stress relaxation.Mooney scorch values were determined on a Mooney Viscometer at 121° C.,and represent the compounds' resistance to premature vulcanization. Thevalues reported were the times required for a five-point rise from theminimum Mooney viscosity at the test temperature. Larger valuesrepresent a resistance to premature vulcanization; shorter timesindicate a tendency to “scorch.”

Oscillating Disk Rheometer (“ODR”), ASTM D2084-01: Standard Test Methodfor Rubber Property-Vulcanization Using Oscillating Disk Cure Meter.This test measures the use of the oscillating disk cure meter fordetermining selected vulcanization characteristics of vulcanizablerubber compounds. The tests were performed at 153° C. The parametersRmin and Rmax are the minimum rheometer torque (before the onset ofvulcanization) and the maximum rheometer torque (due to vulcanization),respectively. The parameter t90 is the time required for the occurrenceof 90% of the increase in torque due to vulcanization (time atR/(Rmax−Rmin)=0.90).

Rebound Resilience, DIN 53512: Determination the rebound resilience ofrubber using the Zwick rebound pendulum for determining the reboundresilience of rubber. The rebound resilience R is the ratio of theenergy recovered to the energy expended.

Hardness, DIN 53505: Shore A and Shore D hardness testing of rubber. TheShore hardness is the resistance exercised by the test material to abody of defined shape being pressed into it under a defined springpressure. Shore A for soft rubber, Shore D for Ebonite/hard rubber.

C. Test Results of Rubber Compositions Containing Various TackifyingResins

Table 5 reports the test results of a 30/70 NR/BR rubber compositioncontaining Resin O or T8000 resin as the tackifying resin. The rubbercomposition containing Resin O has superior tack compared to the rubbercomposition containing T8000.

TABLE 5 Mooney ODR Rebound Tackifying Tack Tack Tack Scorch CureResilience Resin 1 day 3 day 8 day t5 t90 % Resin O 106.5 122.1 149.916.26 8.4 50.4 (4 phr) T8000 101.9 111.7 117.2 15.55 8.24 49.6 (4 phr)

Table 6 reports the test results of a 100% NR composition containingResin O and Resin B as tackifying resins. The control composition(Blank) which did not have any tackifier for comparison purpose has verylow tackiness (0.2) as shown in Table 6. Compared with the Blank, therubber compositions containing Resin O or Resin B as a tackifying resinshow a considerable increase in tackiness.

TABLE 6 Mooney ODR Rebound Tackifying Tack Tack Tack Scorch CureResilience Hardness Resin 1 day 3 day 8 day t5 t90 % Shore A Resin O16.7 15.8 15.7 9.08 10.75 41.8 71 Resin B 17.7 13.9 18.6 8.76 10.69 41.174 Blank 13.6 15.2 11.9 10.17 9.7 43.9 74

Rubber compositions of 70/30 SBR/BR rubbers with various tackifingresins were prepared. Table 7 compares the tack of 70/30 SBR/BR rubbercontaining Resin B, a tackifying resin of the invention, versus knowntackifying resins: T8000, T2300, T6000, and T2000. The Resin Btackifying resin yields superior tack performance in comparison to othertackifying resins.

TABLE 7 Tack Tack Tack Tackifying resin 1 day 3 day 8 day T8000 1.0 0.80.5 T2300 1.0 0.9 0.5 T6000 0.7 0.6 0.6 T2000 0.5 0.4 0.5 Resin B 4.55.1 3.9

1. A modified, hydrocarbylphenol-aldehyde resin prepared by reacting anepoxide with a resin of Formula (I) in the presence of a basic catalystand at a basic pH,

wherein R₁ is a straight or branched C₁-C₃₀ alkyl; R₂ is —CHR₅, whereinR₅ is an amine containing an amino group having at least one activehydrogen atom of the formula (i)

wherein R′ and R″ are independently H, C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆alkynyl, aryl, or wherein R′ and R″, together with the N carrying them,form a 5-7 membered heterocyclic ring; or an alkylene polyamine of theformula (ii)

wherein A is a divalent alkylene radical having 2 to 6 carbon atoms andx is an integer from 1 to 10; R₃ is R₂ or a mixture of R₂ and H and/or—CHR₅OH; R₄ is H or C₁-C₄ alkyl; and m plus n is at least
 1. 2. Themodified, hydrocarbylphenol-aldehyde resin prepared by reacting about 1to about 25 weight percent of an epoxide with a resin of Formula (I). 3.The modified, hydrocarbylphenol-aldehyde resin of claim 1, wherein theepoxide is a straight C₄-C₂₂ alkyl epoxide.
 4. The modified,hydrocarbylphenol-aldehyde resin of claim 3, wherein the epoxide is astraight C₆-C₁₆ alkyl epoxide.
 5. The modified,hydrocarbylphenol-aldehyde resin of claim 1, wherein R₅ is morpholinyl.6. The modified, hydrocarbylphenol-aldehyde resin of claim 1, wherein R₁is a straight or branched C₁-C₁₅ alkyl.
 7. The modified,hydrocarbylphenol-aldehyde resin of claim 6, wherein R₁ is tertiarybutyl or tertiary octyl.
 8. A process for preparing a modified,hydrocarbylphenol-aldehyde resin comprising the step of: (a) reacting anepoxide with a resin of Formula (I) in the presence of a basic catalystand at a basic pH,

wherein R₁ is a straight or branched C₁-C₃₀ alkyl; R₂ is —CHR₅, whereinR₅ is an amine containing an amino group having at least one activehydrogen atom of the formula (i)

wherein R′ and R″ are independently H, C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆alkynyl, aryl, or wherein R′ and R″, together with the N carrying them,form a 5-7 membered heterocyclic ring; or an alkylene polyamine of theformula (ii)

wherein A is a divalent alkylene radical having 2 to 6 carbon atoms andx is an integer from 1 to 10; R₃ is R₂ or a mixture of R₂ and H and/or—CHR₅OH; R₄ is H or C₁-C₄ alkyl; and m plus n is at least
 1. 9. Aprocess for preparing a modified, hydrocarbylphenol-aldehyde resinaccording to claim 8, wherein step (a) comprises reacting about 1 toabout 25 weight percent of the epoxide.
 10. A rubber composition havingimproved tack comprising a rubber or mixtures of rubbers, and 0.5 to 7phr of a modified, hydrocarbylphenol-aldehyde resin of claim 1.